1. Technical Field
The field of art to which this invention pertains may be generally located in the class of devices relating to cutting tools. Class 409, Cutting, Milling, or Planing, United States Patent Office Classification appears to be the applicable general area of art to which the subject matter similar to this invention has been classified in the past.
2. Background Information
This invention relates to a chip breaker for use with rotary cutting tools such as a drill, an annular hole cutter, a milling cutter, and the like.
Rotary cutting tools of the aforementioned type generate a long chip during a metal cutting action. Such long chips are relatively stiff and of a tight spirally round configuration so that they move upwardly through the spiral flutes of a rotary cutter. If the long chips are not broken they tend to travel up the spiral flutes of a rotary cutter and become wound around the arbor carrying the rotary cutter, which creates a retarding action and reduces the rotating rate of the rotary cutter, and requires a greater amount of power to rotate the cutter than is normally required. The operator is thus required to spend time in shutting down the machine operating the rotary cutter, so that the chips wound around the arbor may be removed. Such shut downs for removing the chips increases costs and adds to the cost of machining workpieces. The necessity of removing chips that are wound around a rotary cutter arbor also creates a definite hazzard, because the edges of the chips are usually very sharp and hence the operator is likely likely to experience cuts on his hands while removing the chips wound around the rotary cutter arbor. Winding or clogging up of the chips around a rotary cutter arbor, as described above, also entails the disadvantage of interfering with proper lubrication of a rotary cutter so that the useful life of the rotary cutter is measurably shortened.
Various chip breakers have been employed in the past in an effort to break up chips before they can wrap around an arbor carrying a rotating cutter. One such chip breaker for annular hole cutters is shown and described in U.S. Pat. No. 4,514,120. However, the chip breaker shown in the last mentioned patent is particularly adapted for use with an annular hole cutter, it is not of general use, it requires a bushing member to hold it, and it is expensive to make and time consuming to set up for use.